Refrigerant circulation apparatus utilizing two evaporators operating at different evaporating temperatures

Abstract

A refrigerant circulation apparatus utilizing two evaporators operating at respectively different evaporating temperatures which is capable of efficient refrigerant circulation by performing a heat exchange by contact between a refrigerant pipe guiding refrigerant discharged from a condenser to an evaporator and a refrigerant pipe guiding refrigerant discharged from the evaporator to a compressor in order to enhance the refrigerating ability when an evaporator is operated at a high evaporating temperature and pressure, includes a compressor, a condenser, a plurality of evaporators operating at different respective evaporating temperatures, a first plurality of refrigerant pipes for guiding the refrigerant discharged from the condenser to the plurality of evaporators, and a second plurality of refrigerant pipes predetermined portions of which are in heat exchanging contact with the first plurality of refrigerant pipes.

What is claimed is: 
     
       1. A refrigerant circulation apparatus utilizing plural evaporators having different respective evaporating temperatures, comprising: a compressor;   a condenser;   a plurality of evaporators which are connected in parallel and which have respectively different evaporating temperatures;   a plurality of refrigerant pipes for guiding a refrigerant discharged from the condenser to the plurality of evaporators; and   a heat exchanging means for guiding the refrigerant discharged from the plurality of evaporators to the compressor, including an additional plurality of refrigerant pipes, portions of which are in contact with the plurality of refrigerant pipes which guide the refrigerant from the condenser to the evaporators and exchange heat at contact portions thereof between high temperature refrigerant discharged from the condenser and low temperature refrigerant discharged from the evaporators; wherein the heat exchanging means comprises:     a first heat exchanger formed by a portion of one of said refrigerant pipes guiding the refrigerant discharged from one of the evaporators operating at a high evaporating temperature and pressure among the plurality of evaporators to the compressor being in contact with a first capillary branched from one of the plurality of refrigerant pipes guiding the refrigerant from the condenser to the evaporator at a high evaporating temperature and pressure;   a second heat exchanger formed by a portion of one of said refrigerant pipes guiding the refrigerant discharged from one of the evaporators operating at a low evaporating temperature and pressure among the plurality of evaporators to the compressor being in contact with a second capillary branched from one of the plurality of refrigerant pipes guiding the refrigerant to the condenser to the evaporator at a low evaporating temperature and pressure; and   a third heat exchanger formed by a portion of one of the plurality of refrigerant pipes guiding refrigerant from the condenser to the plurality of evaporators being in contact with the refrigerant pipe guiding refrigerant from the evaporator operating at a high evaporating temperature and pressure through the first heat exchanger to the compressor.   
     
     
       2. The apparatus of claim 1, wherein a unidirectional valve for preventing the counterflow of the refrigerant is provided in the refrigerant pipe guiding the refrigerant discharged from the evaporator operating at a low evaporating temperature and pressure to the compressor. 
     
     
       3. The apparatus of claim 2, wherein the unidirectional valve is a check valve.